title: Exploration of the effects of gender and mild esophagitis on esophageal pain thresholds in the normal and sensitized state of asymptomatic young volunteers.
abstract: BACKGROUND
  Clinical data suggest gender differences in gastrointestinal pain, but very little experimental data exist. Esophageal painful thresholds to mechanical, thermal, electric, and chemical stimuli can be measured with the esophageal multimodal pain model. The aim was to measure the effect of gender and mild esophagitis on esophageal pain perception.
  
  
  METHODS
  Thirty-five healthy asymptomatic volunteers [19 men, median age 29 (22-56 years)] underwent upper GI endoscopy, 24 h pH/impedance measurement, and multimodal esophageal pain stimulation before and after sensitization with acid. Stimulus intensities at painful thresholds were recorded.
  
  
  RESULTS
  Men had higher pain thresholds (PT) to mechanical stimulation (mean volume: men 20.9 ± 10 mL vs women 15.2 ± 6.8 mL, P = 0.02) and more men tolerated the maximum acid challenge (58% vs 20%, P = 0.03). There were no differences between genders for PT to (1) thermal stimulation [mean stimulation time (men, women): heat; 20 ± 5 s vs 21 ± 6 s or cold; 33.3 ± 20.1 s vs 20.7 ± 21.4 s, P > 0.2], (2) electrical current (mean current: men 17.6 ± 9.2 mA vs women 12.9 ± 3.7 mA, P = 0.11), or (3) acid volume [median volume: men 200 (20;200) mL vs women 133 (40;200) mL, P = 0.2]. Fifteen asymptomatic subjects had mild esophagitis (10 men, all Los Angeles A). There were no differences in esophageal PT between subjects with normal endoscopy or mild esophagitis (all P > 0.3).
  
  
  CONCLUSIONS
  The effects of gender and mild esophagitis on esophageal multimodal pain perception have been measured in asymptomatic volunteers. The study suggests that gender, not mild esophagitis, tends to influence mechanical and chemical esophageal pain.
authors.affiliation: Department of Internal Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden. annelundkrarup@gmail.com
authors.forename: A L
authors.initials: AL
authors.lastname: Krarup
authors.forename: J
authors.initials: J
authors.lastname: Gunnarsson
authors.forename: J
authors.initials: J
authors.lastname: Brun
authors.forename: A
authors.initials: A
authors.lastname: Poulakis
authors.forename: A
authors.initials: A
authors.lastname: Edebo
authors.forename: G
authors.initials: G
authors.lastname: Ringström
authors.forename: A M
authors.initials: AM
authors.lastname: Drewes
authors.forename: M
authors.initials: M
authors.lastname: Simrén
mesh_terms: D000143:Acids / Q000009:adverse effects; D000328:Adult; D004941:Esophagitis / Q000139:chemically induced / Q000503:physiopathology; D004947:Esophagus / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017288:Pain Threshold / Q000502:physiology*; D012727:Sex Characteristics; D055815:Young Adult
chemical_list: D000143:Acids
keywords: Asymptomatic; Esophagitis; Esophagus; Experimental; Gender; Healthy; Pain; Sensation; Sensitization